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savanna now shares equal billing with tall-grass 

 prairie as the must threatened plant eonimuni- 

 ties in the Midwest and among the most threat- 

 ened in the world. Only a little more than 200 ha 

 (300 acres) of intact examples of oak savanna 

 vegetation are listed in the Wisconsin State 

 Natural Heritage Inventory, or less than 0.0001 

 (0.01%) of the oiiginal 2.9 million ha (7.3 mil- 

 hon acres) — a fate repeated throughout this 

 community's entire range (Johnson 1986; 

 Smeins and Diamond 1986). A tallying of 

 known oak savanna sites in the upper Midwest 

 (Missouri northward) in 1985 (Nuzzo 1986) 

 listed only 133 sites totaling 2,600 ha (6,420 

 acres), or only 0.0002 (0.027f ) of the estimated 

 presettlement extent of the community. Most of 

 what remains are dry and wet savanna types. 

 Richer, more productive soil savanna is now 

 nearly nonexistent. 



Fortunately, most of the biota that was asso- 

 ciated with savanna, especially the vertebrates, 

 have either adapted to the changed landscape or 

 have managed to survive in suboptimal habitat 

 (e.g., the fringes of other less devastated com- 

 munities, such as oak forests). This situation is 

 precarious for many species, however, and their 

 long-term future is doubtful. Vertebrates have 

 been successful because major elements of the 

 savanna structure are still well represented in 

 various edge habitats, including wooded pas- 

 tures, lawns, and woodlots. The fact that the 

 plant species may be different in surrogate 

 savannas has not affected savanna vertebrate 

 species for the most part. 



Oak savanna vegetation has not fared as 

 well. Many species that were probably savanna 

 specialists are now uncommon and are found 

 only in the fringes and openings of oak woods, 

 brushy areas, and lightly grazed pastures. A few 

 examples are giant false-foxglove (Aitreolarici 

 grcmdiflora), yellow pimpernel (Taenidia inte- 

 gerhina), pale Indian-plantain (Cacalia utripli- 

 cifolia). New Jersey tea {Ceanothiis anieri- 

 canus). sessile-leaved eupatorium {Eupatonum 

 sessilifolium), and white death-camas 

 (Zigademts elegans). Two likely savanna spe- 

 cialists, purple milkweed {Astlepias purpitms- 

 cens) and wild hyacinth {Cainassia scilloides), 

 are now listed as endangered in Wisconsin. 

 Three others — kitten-tails (Besseya biillii). 

 cream gentian (Gentiana alba), and Virginia 

 lespedeza {Lespedeza virginica) — are listed as 

 threatened. 



Most bird species found in Wisconsin savan- 

 nas are still doing well today (e.g., American 

 robin [Tiirdus migratorius]. indigo bunting 

 [Pusserina cyanea]. and brown thrasher 

 [Toxostoma riifuiu]). Only one oak 

 savanna/woodland bird, the passenger pigeon 

 (Ecopistes migratorius), has become extinct, 

 and another, the wild turkey (Meleagris gal- 



lopavo). was extiipated but is now restored; 

 however, both of these were lost because of 

 unregulated hunting and not because of habitat 

 loss. 



Recently, however, a number of savanna 

 birds have not thrived or have begun to decline 

 throughout their range, including the northern 

 nicker (Colapics auratits). red-headed wood- 

 pecker (Meiaiwrpes eiytlinicephaliis). vesper 

 sparrow {Pooi'cetes gramiucus), northern bob- 

 white {Colinii.s virgiiiianiis). warbling vireo 

 {Vireo gilriis). and field sparrow iSpizella piisil- 

 la). The orchard oriole {Icterus spurius) and 

 yellow-breasted chat {Icteria vireiis) are on 

 Wisconsin's list of special concern. The logger- 

 head shrike (Laniiis iudoviciaiuis) and bam owl 

 {Tyto alba) are on Wisconsin's endangered 

 species list, and Bell's vireo ( Vireo bellii) is now 

 on Wisconsin's threatened species list (D.W. 

 Sample and M.J. Mossman, Wisconsin 

 Department of Natural Resources, personal 

 communication, 1994). Although loss of habitat 

 has not been the cause of decline in all these 

 species, it certainly is affecting many of them. 

 The abandonment and loss of savanna/woodlot 

 pastures in the past few decades may be playing 

 a role in some of the recent declines of savanna 

 bird species. 



Most amphibian and reptile species that 

 were closely associated with the historic oak 

 savanna in Wisconsin are doing at least moder- 

 ately well today, although two reptiles associat- 

 ed with savanna habitat are on the Wisconsin 

 list of endangered species and are suffering 

 from habitat loss: the western slender glass 

 lizard (Opliisaurus atteuuatus) and the eastern 

 massasauga rattlesnake (Sistrurus catenatus). 

 The eastern massasauga is also under consider- 

 ation for federal listing. 



Our knowledge of oak savanna invertebrates 

 is limited; we know little about what species 

 were characteristic or restricted to oak savanna. 



Oak savanna. 



